The tragic events that occurred on Sep. 11, 2001 created a new awareness of airborne law enforcement. Prior to Sep. 11, 2001, most government agencies believed that domestic hijacking was a thing of the past. Only thirty-three armed and trained federal air marshals (FAMs) were employed, mainly to protect selected international flights. Federal air marshals operated without the ability to communicate to outside resources because of a lack of standard law enforcement communications equipment that could be used without interfering with existing communications equipment or aircraft operations. With this knowledge, the September 11th terrorists targeted domestic flights that offered the least resistance.
At the present time, thousands of federal air marshals are assigned to improve aviation security by protecting commercial airlines. Unfortunately, these federal air marshals still remain isolated during flights, and do not possess the capability to communicate wirelessly and covertly with each other, with the flight crews, or with any ground-based mission operations center (MOC), for example on airline operations control center or federal air marshal service operations center. Some attempts to secure aeronautical communications for federal air marshals have focused on using SATCOM (satellite communications) links, which include Inmarsat (Aero-I and Aero-H) and Iridium. With an estimated acquisition and installation cost of about $250,000 per aircraft, these SATCOM solutions are cost prohibitive. Installation of such systems on a U.S. commercial airline fleet of nearly 8,000 aircraft would be very expensive. Yet even with this high investment, some of these solutions would fail to provide covert communications.
There have been other proposals to use an Airfone™ air-ground telephone system to assist federal air marshals in their air-ground communications, but that type of communications system is not secure and is not wireless. It also requires a federal air marshal to be tethered to a seatback telephone, jeopardizing the ability of the federal air marshal to remain undercover during flight. Other proposed satellite communications and cellular systems require expensive infrastructure and are not covert and wireless.
Other proposals are set forth in U.S. Pat. Nos. 6,676,078; 6,725,035; and 6,816,087. For example the '078 patent discloses a method and system for alerting a cockpit crew of terrorist activity. FOBs are worn by flight attendants. An antennae sending unit (ASU) is located in the passenger cabin, and a cockpit display unit (CDU) is located in the cockpit of the aircraft. The flight attendant can send an alert signal to the cockpit by sending a coded signal via the ASU to CDU, providing an alert indicator to the cockpit crew. The CDU can also send a transponder code and ACARS message to ground-based units. This system operates similar to a wireless buzzer system. It is activated by a flight attendant, even permitting an alarm to be transmitted to ground at the instigation of the flight deck crew.
In the '087 patent, a warning signal is transmitted by a portable transmitter, which is worn by a flight attendant, who actuates the transmitter to transmit a frequency that does not interfere with any existing avionics and navigational equipment of the aircraft. A receiver located in the flight deck has an audible and visual alarm that alerts the flight crew, who can actuate a radio to transmit to ground an alert signal, for example a hijacking code, on a pre-selected frequency.
The '035 patent is directed to a cellular system repeater located in an aircraft. A vertically polarized signal is emitted from cellular cell towers for operation with an aircraft.
One common problem associated with these systems is their limitation in only communicating primarily with the flight deck, and not interfacing with aeronautical resources for satisfactory air-ground communications or communications with an ICE “scrambling” aircraft, which may have been scrambled to intercept a hijacked commercial airliner. Such communications between a federal air marshal and a ground transceiver or a “scrambling” aircraft could be important to prevent a catastrophe if the scrambling aircraft pilot believes the hijacked aircraft should be targeted to prevent further catastrophes, such as occurred on Sep. 11, 2001.